System Unstable at 1600

[Column]

Here is my rig:

Asus P6T LGA 1366
Intel i7 920 @ 2.66
Cooler Master V8 Heatsink
GSkill 6GB (3 x 2GB) 1600 Model #F3-12800CL8TU-6GBPI
EVGA GTX 275 FTW edition
PC Power & Cooling 750W

The problem I am having is getting my rig to be stable at the rated memory speed of 1600. At 1066 everything runs like a champ but if I try to overclock to 1333 or 1600 I get problems. First I tried using the XMP profile. This at least got me into windows but soon I started having random restarting issues and eventually BSOD 124. Next I tried manually setting the BIOS. Here are the settings I have tried:

DRAM Freq - 1600
Unclk - 3200
QPI/DRAM - 1.32,1.35
Turbo - Disabled
DRAM Volt - 1.60, 1.64

Out of the 3 or 4 tests I have done, most end up with frequent but random restarting and some even ending up with BSOD or even the inability to post. Please help in any possible way. Thanks

[GSKILL TECH]

Make sure you have them installed in the black slots.

Try testing them individually if you continue to have an issue. Your BIOS settings should look like this:

Ai Overclock Tuner - Manual
CPU Ratio Setting - 16
Intel SpeedStep Tech - Disabled
BCLK Frequency - 166
DRAM Frequency - DDR3-1600
UCLK Frequency - 3200MHz
QPI Link Data Rate - AUTO

DRAM Timing Control
CAS Latency - 8
tRCD - 8
tRP - 8
tRAS - 21
Command Rate - 2N

CPU Voltage - 1.30V
CPU PLL Voltage - 1.85V
QPI/DRAM Core Voltage - 1.40V
IOH Voltage - 1.35V
IOH PCIE Voltage - 1.6V
ICH Voltage - 1.20V
ICH PCIE Voltage - 1.60V
DRAM Bus Voltage - 1.64V

Load Line Calibration - Disabled

Let me know if that works.

Thank you
GSKILL SUPPORT

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1st Test

My P6T would not load with my DIMMs in the black slots so I kept them in the orange slots for the test.

Ai Overclock Tuner - Manual
CPU Ratio Setting - 16.0
SpeedStep - Disabled
BCLK - 166

Now because of the BCLK bump my options for the next couple items where different than yours

DRAM Freq - 1664MHz
UCLK Freq - 3327MHz
QPI Link - Auto

Timings - 8 8 8 21 2N

CPU Volt - 1.30
CPU PLL Voltage - 1.86 (did not give me 1.85 option)
QPI/DRAM Volt - 1.40
IOH Volt - 1.36 (did not give me 1.35 option)
IOH PCI Volt - 1.60
ICH Volt - 1.20
ICH PCI Volt - 1.60
DRAM Volt - 1.64

Load Line Calibration - Disabled

Save and exit got me to the Windows load screen then I got BSOD. Any other ideas?

[GSKILL TECH]

Ai Overclock Tuner - Manual
CPU Ratio Setting - 17.0
SpeedStep - Disabled
BCLK - 160

DRAM Freq - 1600MHz
UCLK Freq - 3200MHz
QPI Link - Auto

Timings - 8 8 8 21 2N

CPU Volt - 1.30
CPU PLL Voltage - 1.86
QPI/DRAM Volt - 1.40
IOH Volt - 1.36
IOH PCI Volt - 1.60
ICH Volt - 1.20
ICH PCI Volt - 1.60
DRAM Volt - 1.64

Do you have other timing values available? You may need a new motherboard if the black slots aren't working. Those are the primary slots.

Thank you
GSKILL SUPPORT

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Test 2

According to my motherboard manual the black slots are A2, B2, C2 and it recommends using the orange slots which are A1, B1, C1 for better performace.

Ai Overclock Tuner - Manual
CPU Ratio Setting - 17.0
SpeedStep - Disabled
BCLK - 160

DRAM Freq - 1600MHz
UCLK Freq - 3200MHz
QPI Link - Auto

Timings - 8 8 8 21 2N

CPU Volt - 1.30
CPU PLL Voltage - 1.86
QPI/DRAM Volt - 1.40
IOH Volt - 1.36
IOH PCI Volt - 1.60
ICH Volt - 1.20
ICH PCI Volt - 1.60
DRAM Volt - 1.64


Using this setup windows actually loaded with no problems. Since it seemed to be running fine I decided to start Prime 95. Within the first test I got a BSOD 124. So then I changed it up a bit and went with this setup

Ai Overclock Tuner - Manual
CPU Ratio Setting - 18.0
SpeedStep - Disabled
BCLK - 150

DRAM Freq - 1504MHz
UCLK Freq - 3007MHz
QPI Link - Auto

Timings - 8 8 8 21 2N

CPU Volt - 1.30
CPU PLL Voltage - 1.86
QPI/DRAM Volt - 1.40
IOH Volt - 1.36
IOH PCI Volt - 1.60
ICH Volt - 1.20
ICH PCI Volt - 1.60
DRAM Volt - 1.64

With the lower BCLK this setup was rock solid. I ran Prime 95 all night and everything was still running smooth when I woke up. With that said should I try now just bumping up in small increments to see at what point the system becomes unstable? If you could not tell I am pretty new to this stuff so I may be missing something that you won't. Thanks a ton for your help so far! You guys are super fast at responding.

[GSKILL TECH]

Good job! Seems like your BCLK is maxed at ~150 with QPI/DRAM Volt - 1.40. You may need to increase that as you up the BCLK to see how high it will go. Try CPU Volt - 1.35 / QPI/DRAM Volt - 1.50
and that should run BCLK 160+

Keep me posted on the results

Thank you
GSKILL SUPPORT

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Yet another Test

Increasing QPI/DRAM to 1.50 and CPU Volt to 1.35 seems to be doing the trick. BLCK is back to 160 with a CPU ratio of 18. So this means my memory is finally running smooth at 1600! I am going to let Prime 95 run overnight but so far it looks good. Thanks for all the help, from here I am going to try and get my CPU to at least 3.2 hopefully.

Now that we got this memory working fine I have another question. From what I have been reading QPI/DRAM is one of those voltages that some people seem to say it should not go over a certain range. I have seen it range from as low as 1.35 to as high as 1.45. I have also heard that the QPI should stay within a certain range of my DRAM volt. Some saying .5 others .3 and even others saying .03. Have you heard any of these claims and are any of them true? I want my memory to run at 1600 but not at the expense of my system. Thanks again for all your help.

[Tradesman]

If it stays stable and you OC a bit you may be able to drop this voltage a tad, because ASUS expects the 1600 speed to be under an OC

[Column]

Since I am farily new to overclocking let me see if I understand your reply correctly Tradesman. To get to my desired clock speed of 3.2 I would need to just change the CPU ratio to x20. Once I make sure this is stable I should then be able to drop the QPI a bit without sacrificing my memory speed of 1600? Should I just keep lowering the QPI/DRAM till it becomes unstable? Sorry for the newbish questions, I just want to make sure I am doing this right.

[Tradesman]

Basically yes, to a degree right now your depending on juice to keep things up, OCing the CPU a bit will in a way 'power it up' more and be more active in the running of the MC, which quite often results in letting you lower the RAM voltage some, it can get complicated, but that's basically it. You'll often see mobos that say they will run high spped RAM and have an '(OC)' next to the RAM speed, which is indicative of being in an OC situation.

[GSKILL TECH]

Essentially you want to have the voltages as low as possible. What I would suggest is lowering QPI/DRAM Voltage to 1.4V while keeping CPU VCore at 1.35V.. see how low it will go until unstable. Then lower CPU VCore until it is unstable. If you can get QPI/DRAM Voltage to 1.35V-1.4V and CPU VCore to about 1.32V, that would be ideal. Right now we don't know which one was causing the instability originally.

Thank you
GSKILL SUPPORT

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Final Tests

Ok, after several days of testing I think I finally have my system at a safe but fast speed. What I decided to do is lower my Vcore and QPI to the range that I felt comfortable at and then tried to overclock my CPU as high as it could go at those voltages without being unstable. Once I got to a rock solid CPU speed then I tried lowering the VCore and QPI to see how low I could get them. Here are my final BIOS settings.

AI Overclock Tuner - Manual
CPU Ratio - 18
Intel SpeedStep - Disabled
BCLK - 190
PCIE - 100
Dram Freq - 1523
UCLK Freq - 3047
QPI Link Data Rate - Auto

Dram Timings - 8,8,8,21,2N

CPU Volt - 1.32
CPU PLL Volt - 1.88
QPI/DRAM Volt - 1.40
IOH Volt - 1.10
IOH PCIE Volt - 1.50
ICH Volt - 1.20
ICH PCIE Volt - 1.60
DRAM Bus Volt - 1.64

Load Line Calibration - Disabled

I believe most of my instablity in the begining was from my QPI/DRAM Volt. With memory speeds of 1500 and above it will not take anything less than 1.40. I tried lowering it to 1.35 but only got BSOD 124. When I tried to get my memory speeds at or above 1600 it seems to need at least a QPI/DRAM Volt of at least 1.50 and I was not comfortable with that voltage. In the end I got my CPU to 3.42 and my memory above 1500 so I am very happy with the results.

Running 3DMark06 at Default BIOS setting I got a score in the 16000's (I forget the actual score since I did not save it). With my overclocked settings I got a high score of 20373 so the difference in settings definately shows. Thanks a ton guys for helping me get my new rig running up to speed! I will definately be buying GSKILL products in the future because of the great customer service you guys provide, top notch!!!

[Tradesman]

Glad the OC helped....and by the way, Nice OC, Keep an eye on your CPU temps for a while, and you should be good to go.

Have a Gud 1 !

Tman

[GSKILL TECH]

Those are good 3DMark06 numbers! Glad to hear everything works well.

Thank you
GSKILL SUPPORT